Funky IS wrong alot, but this is one of those times when he's actually correct
Kies Air will use a WiFi connection between your phone and computer to transfer the files, so it won't eat into your data plan. To be on the safe side, you should be sure your mobile data connection is turned off.
Sent from my rooted, debloated, deodexed Sinclair ZX-80 running CM -0.001 using Tapatalk 2